1. Field of the Invention
This invention relates generally to inserters and more particularly to ram mechanisms for driving enclosures.
2. Brief Description of the Prior Art
Inserters have played a significant role among the labor saving devices available to businesses which are engaged in the daily mailing of large numbers of pieces. Among the advantages of inserter usage has been the reduction in personnel required to process large quantities of outgoing mail. Further, mail room personnel have been relieved of the monotonous task of individually stuffing a seemingly insurmountable number of envelopes. Inserters have been particularly well adapted for use in the mailing of form letters and the like and have been employed for the insertion of personalized documents, e.g. computer generated checks, tab cards, etc. into window envelopes.
In U.S. Pat. No. 2,914,895 issued Dec. 1, 1959 to Samuel W. Martin and assigned to the assignee of the present invention, an envelope inserter having a reciprocating ram blade with an enclosure pusher secured to the blade undersurface has been described. The ram blade was mounted for reciprocal movement along a horizontal plane from a home position in front of an enclosure pick-up station to an envelope station. The pusher engaged the enclosure beneath the ram blade and drove it into the envelope.
Among the problems encountered with prior inserters was that the ram blade was required to return to its home position before the next enclosure could be loaded into the pick-up station. This was an important factor for consideration whenever attempts were made at improving throughput. In the Pitney Bowes Model 3320 inserter which employed a ram mechanism similar to that described in U.S. Pat. No. 2,914,895, the maximum throughput with tab cardenclosures was 3,200 cards per hour on an operational basis.
If attempts to improve throughput were made, the general thrust of such attempts was to increase cycle speeds. Such attempts could not be successful due to increased component wear, high noise levels and jamming. Thus, output rates could not be significantly increased due to the physical limitations of the various components. Prior attempts at increasing throughput by increasing the cycle speeds of components did not serve to reduce the significant dwell time which was required while waiting for completion of the ram return stroke.
In prior ram mechanisms the enclosure pusher was mounted beneath the ram blade. The pusher was secured in its position by a threaded screw. Often adjustment of the pusher relative to the new blade was required. To adjust the position of the pusher for accommodation of variations in enclosure widths, it was necessary for an operator to employ a screwdriver. This task was difficult for some mail room personnel.